In the evolving digital economy, consumer behaviour has undergone a fundamental transformation driven by technological advancements, algorithmic personalization, and behavioural targeting. Traditional economic theories that assumed rational decision-making no longer capture the complexities of online consumer choices. This study aims to explore how behavioural economics principles—particularly cognitive biases, heuristics, and digital nudges—shape consumer purchase intentions in the digital marketplace. The research investigates how elements such as scarcity cues, anchoring effects, social proof, and default options embedded in online interfaces subtly influence consumer preferences and willingness to buy. Using an integrated behavioural-economic framework, the study combines insights from psychology, marketing, and microeconomics to analyse digital decision-making processes. Primary data will be collected through structured questionnaires and controlled digital experiments among online consumers, while secondary data will be derived from peer-reviewed journals and marketing analytics reports. Statistical techniques such as Structural Equation Modelling (SEM) and Regression Analysis will be employed to examine causal relationships between behavioural factors and purchase intent. It is expected to demonstrate that digital nudging mechanisms significantly impact consumer decision-making, often leading to suboptimal or impulsive purchases that deviate from rational choice theory. Furthermore, the research will highlight how the degree of trust, perceived value, and online transparency moderates these behavioural effects. The study contributes to the growing body of knowledge in behavioural economics by bridging the gap between economic rationality and digital consumer psychology, offering a new lens to understand consumption patterns in data-driven environments. The research aims to assist marketers, policy makers, and digital platform designers in creating ethically sound and consumer-centric digital experiences. It also underscores the need for consumer education and regulatory frameworks to mitigate manipulative digital nudging and protect buyer autonomy. Ultimately, The researchers in this research study aspires to redefine consumer behaviour models for the digital age—where emotion, cognition, and economics converge to shape purchasing realities.